Characterization of a second transcription initiation element (STIE) in the human interleukin-1 beta (IL-1beta) gene.
Interleukin-1-beta (IL-1beta) is a significant mediator in the inflammation process. Although the human IL-1beta genomic sequence has been known for several years, our understanding of its molecular regulation of transcription remains incomplete. We are reporting a new transcription initiation element that is located within intron 1 and exon 2 of the human IL-1beta gene. Different lengths of the human IL-1beta gene fragment (-685 to +550) were cloned upstream from a chloramphenical acetyltransferase (CAT) gene to make the IL-1beta promoter/CAT reporter constructs. Transient CAT expression with these constructs in the human monocytic leukemia cell line THP1 illustrates an important positive regulatory element exists within the region from +387 to +550. Using electromobility shift assays and by DNase I footprinting analysis, we identified three nuclear factor binding sites (+448 to +502, +513 to +531, and +539 to +548). Functional studies show that CAT production is undetectable when the 19 bp region (+513 to +531) is removed, and CAT production is diminished when the 10-bp region (+539 to +548) is deleted. The region containing these sites is likely to initiate a new transcript starting at +559 of exon 2. This second transcript of the IL-1beta gene shares the same reading frame with the previously recognized cDNA transcript.
Zhang
G
G
University Department of Molecular Medicine, Royal Hallamshire Hospital, Sheffield, UK.
Duff
G W
GW
D001483:Base Sequence; D018983:DNA Footprinting; D004268:DNA-Binding Proteins / Q000378:metabolism; D005091:Exons; D005786:Gene Expression Regulation; D006801:Humans; D007375:Interleukin-1 / Q000235:genetics*; D007438:Introns; D009687:Nuclear Proteins / Q000378:metabolism; D012333:RNA, Messenger / Q000235:genetics; D014158:Transcription, Genetic; D014407:Tumor Cells, Cultured
D004268:DNA-Binding Proteins; D007375:Interleukin-1; D009687:Nuclear Proteins; D012333:RNA, Messenger